Stopper rod positioning and control apparatus for control of molten metal flow through a nozzle

Abstract

A stopper rod positioning and control apparatus is provided for controlling the flow of a molten metal out of a bottom nozzle in a metal reservoir. The stopper rod can be aligned with the nozzle's opening by selectively rotating a pair of roller (ring) bearings that are centerline offset from each other along a first axis around which one end of an extended structural arm can pivot where the opposing end of the arm retains the stopper rod along a second axis parallel to the first axis. When the appropriate relative positions of the pair of roller bearings are located for a nozzle-centered stopper rod, the second axial position of the stopper rod is fixed by retaining the appropriate relative positions with a brake mechanism. In a dual nozzle bottom pour reservoir of molten metal a separate stopper rod positioning and control apparatus is provided for each of the two nozzles while a dual nozzle assembly may be utilized to facilitate replacement of a worn nozzle or alter the distances between the centers of the two nozzles.

The invention claimed is: 
     
       1. A method of aligning a stopper rod attached to a positioning and control apparatus with a nozzle disposed in the bottom of a molten metal holding reservoir where the positioning and control apparatus comprises: a lift apparatus centered on a substantially vertically oriented longitudinal axis, the lift apparatus having an inner tube telescopically mounted within an outer tube, the inner tube being reciprocally movable along the substantially vertically oriented longitudinal axis; a servomotor fixedly mounted at a lower end of the outer tube, the servomotor having a servomotor output interconnected to the inner tube whereby actuation of the servomotor results in reciprocal movement of the inner tube along the substantially vertically oriented longitudinal axis; a lower ring bearing having a lower ring bearing outer race and a lower ring bearing inner race, a vertically oriented central axis of the lower ring bearing offset from the substantially vertically oriented longitudinal axis, the lower ring bearing outer race fastened to a telescoping end of the inner tube by a lower ring bearing outer race mounting plate fastened to a slide angle plate to reciprocally move the lower ring bearing along the substantially vertically oriented longitudinal axis with the inner tube; an upper ring bearing having an upper ring bearing outer race and an upper ring bearing inner race, a vertically oriented central axis of the upper ring bearing offset from the substantially vertically oriented longitudinal axis and the vertically oriented central axis of the lower ring bearing; an adjustment plate respectively attached on opposing sides to the lower ring bearing inner race and the upper ring bearing outer race to rotate the upper ring bearing outer race with the lower ring bearing inner race; a locking plate attached to the upper ring bearing inner race to rotate the locking plate with the upper ring bearing inner race about the vertically oriented central axis of the upper ring bearing; a brake assembly having a means for locking the locking plate in a locked position to inhibit rotation of the locking plate; and an arm having a first arm end and a second arm end, the first arm end attached to the locking plate to rotate the arm about the vertically oriented central axis of the upper ring bearing, the second arm end extending at least in the horizontal direction away from the substantially vertically oriented longitudinal axis, the stopper rod depending from the second end of the arm, the method comprising the steps of simultaneously rotating the adjustment plate and rotating the arm until the stopper rod is centered in a plane over the opening in the nozzle, and locking the locking plate in the locked position when the stopper rod is centered in the plane over the opening in the nozzle. 
     
     
       2. The method of  claim 1  further comprising the step of providing a linear extension element between the second arm end and the stopper rod to center the stopper rod in the plane over the opening in the nozzle. 
     
     
       3. The method of  claim 1  further comprising the steps of positioning the lift apparatus relative to an X-Y table with the substantially vertically oriented longitudinal axis perpendicular to the horizontal motion planes of the X-Y table so that adjustment of the X-Y table moves the substantially vertically oriented longitudinal axis in a horizontal plane to center the stopper rod in the plane over the opening in the nozzle. 
     
     
       4. A stopper rod positioning and control apparatus for control of molten metal flow through a nozzle disposed in a bottom of a molten metal holding reservoir, the stopper rod positioning and control apparatus comprising:
 a lift apparatus centered on a substantially vertically oriented longitudinal axis, the lift apparatus having an inner tube telescopically mounted within an outer tube, the inner tube being reciprocally movable along the substantially vertically oriented longitudinal axis; 
 a servomotor fixedly mounted at a lower end of the outer tube, the servomotor having a servomotor output interconnected to the inner tube whereby actuation of the servomotor results in reciprocal movement of the inner tube along the substantially vertically oriented longitudinal axis; 
 a lower ring bearing having a lower ring bearing outer race and a lower ring bearing inner race, a vertically oriented central axis of the lower ring bearing offset from the substantially vertically oriented longitudinal axis, the lower ring bearing outer race fastened to a telescoping end of the inner tube by a lower ring bearing outer race mounting plate fastened to a slide angle plate connected to the telescoping end to reciprocally move the lower ring bearing along the substantially vertically oriented longitudinal axis with the inner tube; 
 an upper ring bearing having an upper ring bearing outer race and an upper ring bearing inner race, a vertically oriented central axis of the upper ring bearing offset from the substantially vertically oriented longitudinal axis and the vertically oriented central axis of the lower ring bearing, the upper ring bearing outer race attached to the lower ring bearing inner race by an adjustment plate to rotate the upper ring bearing outer race with the lower ring bearing inner race; 
 a locking plate attached to the upper ring bearing inner race to rotate the locking plate with the upper ring bearing inner race about the vertically oriented central axis of the upper ring bearing; 
 a brake assembly having a means for locking the locking plate in a locked position to prevent rotation of the locking plate; 
 an arm having a first arm end and a second arm end, the first arm end attached to the locking plate to rotate the arm about the vertically oriented central axis of the upper ring bearing, the second arm end extending at least in the horizontal direction away from the substantially vertically oriented longitudinal axis; and 
 a stopper rod depending from the second end of the arm; 
 
       whereby the stopper rod is centered in a plane over the nozzle by the combined movements of rotating the lower ring bearing inner race about the vertically oriented central axis of the lower ring bearing and rotating the upper ring bearing inner race about the vertically oriented central axis of the upper ring bearing to an aligned stopper rod position centered in the plane over the nozzle, then locking the aligned stopper rod position by the means for locking the locking plate in the locked position, and thereafter reciprocally moving the stopper rod above the nozzle by actuation of the servomotor. 
     
     
       5. The stopper rod positioning and control apparatus of  claim 4  further comprising a linear guide assembly comprising a stationary base and a sliding element, the slide angle plate extending from an upper end of the sliding element and passing through the substantially vertically oriented longitudinal axis, the stationary base supporting the weight of the servomotor and lift apparatus. 
     
     
       6. The stopper rod positioning and control apparatus of  claim 4  further comprising an interior passage in the stopper rod for supply of a neutralizing gas to the tip of the stopper rod when the stopper rod is seated in the nozzle. 
     
     
       7. The stopper rod positioning and control apparatus of  claim 4  further comprising a means for reversibly rotating the tip of the stopper rod when the tip is seated in the nozzle. 
     
     
       8. A stopper rod positioning and control apparatus for control of molten metal flow through a nozzle disposed in the bottom of a molten metal holding reservoir, the stopper rod positioning and control apparatus comprising:
 an outer tube having a substantially vertically oriented longitudinal axis; 
 an inner tube telescopically mounted within the outer tube, the inner tube being reciprocally movable along the substantially vertically oriented longitudinal axis; 
 a lower ring bearing having a lower ring bearing outer race and a lower ring bearing inner race, a vertically oriented central axis of the lower ring bearing offset from the substantially vertically oriented longitudinal axis, the lower ring bearing outer race fastened to a telescoping end of the inner tube by a lower ring bearing outer race mounting plate fastened to a slide angle plate connected to the telescoping end to reciprocally move the lower ring bearing along the substantially vertically oriented longitudinal axis with the inner tube; 
 an upper ring bearing having an upper ring bearing outer race and an upper ring bearing inner race, a vertically oriented central axis of the upper ring bearing offset from the substantially vertically oriented longitudinal axis and the vertically oriented central axis of the lower ring bearing, the upper ring bearing outer race attached to the lower ring bearing inner race by an adjustment plate to rotate the upper ring bearing with the lower ring bearing inner race; 
 an arm having a first arm end and a second arm end, the arm being attached to the upper ring bearing inner race by a locking plate adjacent to the first arm end to rotate the arm about the vertically oriented central axis of the upper ring bearing; 
 a stopper rod depending from the second end of the arm; and 
 a means for locking the upper ring bearing inner race in a fixed position; 
 
       whereby the stopper rod is centered in a plane over the nozzle by the combined movements of rotating the lower ring bearing inner race about the vertically oriented central axis of the lower ring bearing and rotating the upper ring bearing inner race about the vertically oriented central axis of the upper ring bearing to an aligned stopper rod position centered in the plane over the nozzle, then fixing the aligned stopper rod position by the means for locking the upper ring bearing inner race. 
     
     
       9. A system for controlling the flow of a molten metal in a dual pour process, the system comprising:
 a molten metal holding reservoir; 
 a pair of spaced-apart nozzles through which the molten metal flows in the dual pour process, the pair of spaced-apart nozzles disposed in the bottom of the molten metal holding reservoir; 
 a pair of stopper rod positioning and control apparatus, each one of the pair of stopper rod positioning and control apparatus exclusively controlling the molten metal flow through one of the pair of spaced-apart nozzles, each one of the pair of stopper rod positioning and control apparatus comprising:
 a lift apparatus centered on a substantially vertically oriented longitudinal axis, the lift apparatus having an inner tube telescopically mounted within an outer tube, the inner tube being reciprocally movable along the substantially vertically oriented longitudinal axis; 
 a servomotor fixedly mounted at a lower end of the outer tube, the servomotor having a servomotor output interconnected to the inner tube whereby actuation of the servomotor results in reciprocal movement of the inner tube along the substantially vertically oriented longitudinal axis; 
 a lower ring bearing having a lower ring bearing outer race and a lower ring bearing inner race, a vertically oriented central axis of the lower ring bearing offset from the substantially vertically oriented longitudinal axis, the lower ring bearing outer race fastened to a telescoping end of the inner tube by a lower ring bearing outer race mounting plate fastened to a slide angle support connected to the telescoping end to reciprocally move the lower ring bearing along the substantially vertically oriented longitudinal axis with the inner tube; 
 an upper ring bearing having an upper ring bearing outer race and an upper ring bearing inner race, a vertically oriented central axis of the upper ring bearing offset from the substantially vertically oriented longitudinal axis and the vertically oriented central axis of the lower ring bearing, the upper ring bearing outer race attached to the lower ring bearing inner race by an adjustment plate to rotate the upper ring bearing outer race with the lower ring bearing inner race; 
 a locking plate attached to the upper ring bearing inner race to rotate the locking plate with the upper ring bearing inner race about the vertically oriented central axis of the upper ring bearing; 
 a brake assembly having a means for locking the locking plate in a locked position to prevent rotation of the locking plate; 
 an arm having a first arm end and a second arm end, the first arm end attached to the locking plate to rotate the arm about the vertically oriented central axis of the upper ring bearing, the second arm end extending at least in the horizontal direction away from the substantially vertically oriented longitudinal axis; and 
 a stopper rod depending from the second end of the arm; 
 
 
       whereby the stopper rod of each one of the pair of stopper rod positioning and control apparatus is centered in a plane over the one of the pair of spaced-apart nozzles by the combined movements of rotating the lower ring bearing inner race about the vertically oriented central axis of the lower ring bearing and rotating the upper ring bearing inner race about the vertically oriented central axis of the upper ring bearing to an aligned stopper rod position centered in the plane over the one of the pair of spaced-apart nozzles, then locking the aligned stopper rod position of each one of the pair of stopper rod positioning and control apparatus by the brake assembly, and thereafter reciprocally moving the stopper rod of each one of the pair of stopper rod positioning and control apparatus above the one of the pair of spaced-apart nozzles by actuation of the servomotor. 
     
     
       10. The system for controlling the flow of a molten metal in a dual pour process of  claim 9  wherein the pair of spaced-apart nozzles comprise a first unitary dual nozzle block. 
     
     
       11. The system for controlling the flow of a molten metal in a dual pour process of  claim 10  wherein the distance between the pair of spaced-apart nozzles in the first unitary dual nozzle block can be changed by replacing the first unitary dual nozzle block with a second unitary dual nozzle block having the same overall dimensions as the first single dual nozzle block, the spaced-apart distance between the pair of spaced-apart nozzles in the second unitary dual nozzle block being different from the spaced-apart distance between the pair of pair of spaced-apart nozzles in the first unitary dual nozzle block. 
     
     
       12. The system for controlling the flow of a molten metal in a dual pour process of  claim 10 , wherein at least one of the pair of stopper rod positioning and control apparatus further comprises an X-Y table with the substantially vertically oriented longitudinal axis perpendicular to the horizontal motion planes of the X-Y table so that adjustment of the X-Y table moves the substantially vertically oriented longitudinal axis in a horizontal plane to center the stopper rod of the at least one of the pair of stopper rod positioning and control apparatus in the plane over the one of the pair of spaced-apart nozzles for the at least one of the pair of stopper rod positioning and control apparatus. 
     
     
       13. The system for controlling the flow of a molten metal in a dual pour process of  claim 11  wherein at least one of the pair of stopper rod positioning and control apparatus further comprises a linear extension element connected between the second arm end and the stopper rod to center the stopper rod of the at least one of the pair of stopper rod positioning and control apparatus in the plane over the one of the pair of spaced-apart nozzles for the at least one of the pair of stopper rod positioning and control apparatus. 
     
     
       14. The system for controlling the flow of a molten metal in a dual pour process of  claim 9  further comprising a pair of serially indexed molds positioned below the bottom of the molten metal holding reservoir so that the sprue cup of each one of the pair of serially indexed molds is located below one of the pair of spaced-apart nozzles. 
     
     
       15. The system for controlling the flow of a molten metal in a dual pour process of  claim 11  further comprising a pair of serially indexed molds positioned below the bottom of the molten metal holding reservoir so that the sprue cup of each one of the pair of serially indexed molds is located below one of the pair of spaced-apart nozzles, and the spaced-apart distance between the opening in the sprue cup in each one of the pair of serially indexed molds determines the distance between the pair of spaced-apart nozzles in the first or second unitary dual nozzle block. 
     
     
       16. The system for controlling the flow of a molten metal in a dual pour process of  claim 9  further comprising a pair of molds indexed in parallel below the bottom of the molten metal holding reservoir so that the sprue cup of each one of the pair of molds indexed in parallel is located below one of the pair of spaced-apart nozzles. 
     
     
       17. The system for controlling the flow of a molten metal in a dual pour process of  claim 11  further comprising a pair of molds indexed in parallel below the bottom of the molten metal holding reservoir so that the sprue cup of each one of the pair of molds indexed in parallel is located below one of the pair of spaced-apart nozzles, and the spaced-apart distance between the opening in the sprue cup in each one of the pair of molds indexed in parallel determines the distance between the pair of spaced-apart nozzles in the first or second unitary dual nozzle block. 
     
     
       18. A stopper rod positioning and control apparatus for control of molten metal flow through a nozzle disposed in a bottom of a molten metal holding reservoir, the stopper rod positioning and control apparatus comprising:
 a lift apparatus centered on a substantially vertically oriented longitudinal axis, the lift apparatus having an inner tube telescopically mounted within an outer tube, the inner tube having a telescoping end and being reciprocally movable along the substantially vertically oriented longitudinal axis; 
 a servomotor fixedly mounted at a lower end of the outer tube, the servomotor having a servomotor output interconnected to the inner tube whereby actuation of the servomotor results in reciprocal movement of the inner tube along the substantially vertically oriented longitudinal axis; 
 a lower ring bearing having a lower ring bearing outer race and a lower ring bearing inner race, a central axis of the lower ring bearing offset from the substantially vertically oriented longitudinal axis; 
 a linear guide assembly comprising a stationary base, a sliding element and a slide angle plate, the slide angle plate passing through the substantially vertically oriented longitudinal axis, a mounting plate fastened to the upper end of the sliding element and the slide angle plate, the slide angle plate connected to the telescoping end of the inner tube and the lower ring bearing outer race attached to the mounting plate, the stationary base supporting the weight of the servomotor and lift apparatus; 
 an upper ring bearing having an upper ring bearing outer race and an upper ring bearing inner race, a central axis of the upper ring bearing offset from the substantially vertically oriented longitudinal axis and the central axis of the lower ring bearing, the upper ring bearing outer race attached to the lower ring bearing inner race by an adjustment plate and rotatable with the lower ring bearing inner race; 
 a locking plate attached to the upper ring bearing inner race and rotatable with the upper ring bearing inner race about the central axis of the upper ring bearing; 
 a brake assembly having a means for locking the locking plate in a locked position to prevent rotation of the locking plate; 
 an arm having a first arm end and a second arm end, the first arm end attached to the locking plate, the arm rotatable about the central axis of the upper ring bearing, the second arm end extending at least in the horizontal direction away from the substantially vertically oriented longitudinal axis; and 
 a stopper rod depending from the second end of the arm; 
 
       whereby the stopper rod is aligned with the nozzle by the combined movements of rotating the lower ring bearing inner race about the central axis of the lower ring bearing and rotating the upper ring bearing inner race about the central axis of upper ring bearing to an aligned stopper rod position, then locking the aligned stopper rod position by the means for locking the locking plate in a locked position, and thereafter reciprocally moving the stopper rod above the nozzle by actuation of the servomotor.